add subjects and reviwers query

app/graphql/sources/active_record.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+module Sources
+  class ActiveRecord < GraphQL::Dataloader::Source
+    def initialize(model_class)
+      @model_class = model_class
+    end
+
+    def fetch(ids)
+      records = @model_class.where(id: ids).index_by(&:id)
+      records.slice(*ids).values
+    end
+  end
+end